Several U.S. discount retailers recalled packages of ground cinnamon after federal health officials warned that they were contaminated with high levels of lead.

The U.S. Food and Drug Administration issued a safety alert for six brands of cinnamon, including those sold at Dollar Tree and Family Dollar stores.

The move followed massive recalls last fall of WanaBana and other brands of cinnamon applesauce pouches linked to nearly 500 reports of lead poisoning in young children in 44 states. The FDA tested retail samples of spices to determine whether other products were contaminated.

The new recalls are raising questions about the safety of cinnamon, a popular spice found in many American kitchens.

Here’s what you should know:

Recalls have been issued for Marcum and Supreme Tradition brand ground cinnamon sold at Dollar Tree, Family Dollar and Save A Lot stores nationwide.

Other recalls include El Chilar brand cinnamon sold at La Joya Morelense in Baltimore, Maryland; and Swad cinnamon powder sold at Patel Brothers stores across the U.S.

FDA officials said they have not been able to contact MTCI of Santa Fe Springs, California, which distributes MK brand cinnamon sold at SF Supermarkets in several states.

FDA tests found lead levels ranging from 2 parts per million to 4 parts per million in the recalled cinnamon. That’s far lower than the 2,000 to 5,000 parts per million detected in the ground cinnamon from Ecuador that contaminated the applesauce pouches.

There is currently no FDA limit for heavy metals in spices. However, the agency has set a limit of 1 part per million of lead in candy likely to be consumed by small children.

In some cases, spices have been mixed with substances, including lead, to boost color or weight, increasing the value of the product. FDA officials have said that the applesauce pouches may have been intentionally contaminated for this type of economic reason.

No amount of lead is safe, so it should be avoided, health officials said. Because spices are used in such small amounts, the potential harm of any single use is small, but damage could occur after weeks or months of exposure.

Lead can cause long-term problems in adults, including greater risk of high blood pressure, heart disease and kidney damage. Lead is especially harmful to children, where it can cause problems with basic intelligence, learning and behavior.